A sunken utopia sets the stage for a fascinating shooter.

Typically, first-person shooters are a lot like virtual shooting galleries: Great fun, yes, but not exactly thought-provoking.

So it's nice when an FPS comes along that's trying to be something more -- and even better when it actually succeeds. Sometimes you know it in the first few minutes. Take Half-Life: Unlike every FPS before it, the landmark game didn't start with you blasting away. Instead, you found yourself on a train bound for work, and you knew right away: This is gonna be different.

BioShock's opening scene feels like a grandiose homage to Half-Life's: You're treated to a submarine "fly-by" of Rapture, a sprawling metropolis built under the Atlantic, and welcomed by the city's mastermind, Andrew Ryan, via a prerecorded greeting. Ryan (a play on Ayn Rand -- the game's concept draws heavily from Atlas Shrugged) confidently explains his vision of a society founded on the principle "no gods or kings; only man." It's a place where the elite -- scientists, artists, and entrepreneurs -- could fully realize their potential, unhindered by the dead weight of morality, laws, and lesser citizens.

Ryan makes an impassioned case for Rapture, and it looks stunning on approach, a monument to art-deco design. But then you dock and see there's trouble in paradise.

The city's in ruins: Flickering lights reveal rubble-covered marble floors, seawater rolls off elegant balconies, and rotting corpses wear suits and cocktail dresses. Worse, most of the survivors are twisted due to "splicing" -- Rapture's genetic-modification program, used to make the populace stronger, faster, smarter, and apparently psychotic. Whoops.

Also wandering Rapture are "Little Sisters" -- pale, ghoulish little girls who skip from corpse to corpse, harvesting genetic material from the dead. They run with muscle: "Big Daddies," their hulking escorts who are clad in armored diving suits and speak in low, resonating moans that sound like whale songs. The pairs generally ignore you, but if you so much as point a gun at one, watch out.

Ultimately, the Little Sisters are the key to unraveling what the hell happened in Rapture. How to deal with them is less clear. Via radio, two strangers urge you to take completely different courses of action: One tells you the Sisters are no longer human and should be "harvested" (i.e., killed) for the resource they're collecting; the other tells you the awful process that made them Little Sisters can be reversed and asks you to have mercy on them.

Each accuses the other of lying. So when you've finally brought down a Big Daddy after the fight of your life and are holding a struggling Little Sister in your hands -- what now? Harvest the little monster and grow stronger, or free her and face Rapture's crazed citizenry defenseless?

It quickly becomes apparent that BioShock is a game of ideas, moral conundrums, and the horrors of a utopia gone wrong. As you walk through the drowning city, the spectacles are many. There's a mother weeping over an empty baby carriage, the ruined theater where a lunatic entertains an audience of mannequins, and the eerie "Little Wonders" complex, where the Little Sisters were made: a perverse morgue cum preschool littered with childish drawings of their gruesome profession.

That BioShock looks and sounds better than any other game -- and plays just as beautifully -- is just the cherry on top. If our scale went to 11, BioShock would earn it. It is, in a word, rapturous.